Fabric column and pad concrete form

ABSTRACT

A lightweight and flexible concrete forming tube for columns and pads is disclosed, wherein the tube has a very thin wall of high strength fabric and a longitudinal fabric tab running the length of the tube. The tab is sandwiched between two vertical support members made of lumber. The vertical support members and attached fabric tube are then accurately located and braced. As the interior of the tube is filled with concrete, the hydrostatic pressure causes the tube to form a cylindrical shape, thereby accurately aligning itself across from the vertical support members. The use of fabric prevents the problems associated with using cardboard forms, which weaken when exposed to moisture.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of Ser. No. 10/689,639 the disclosure of which is incorporated herein by reference which claims priority under 35 U.S.C 119(e) to the U.S. Provisional Patent Application No. 60/420,029 filed on Oct. 22, 2002, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to a concrete column and pad forming tube made of a fabric like material for receiving a flowable and settable material poured into the interior of the tube so as to form a round column or pad upon the hardening of the material, and which is characterized by folding flat for storage and shipping, while at the same time being able to be accurately positioned on the job site.

BACKGROUND OF THE INVENTION

Concrete column forming tubes are conventionally formed of multiple layers of paper, which are spirally wound around a mandrel and with a wall thickness of about 6 mm so that the tube is rigid and maintains it's circular cross section. Because of the large diameters and lengths, transportation and storage is very expensive.

In an effort to overcome these problems, it was proposed in U.S. Pat. No. 5,376,316 to have extremely thin and flexible paper walls, which would render the tube collapsible into a flat form so as to avoid the high transportation and storage expenses of the rigid cardboard tubes. While the use of the thin walls did make the tube collapsible, the following problems resulted: First, there was no means of holding the tube in position so that when filled with concrete, the column was correctly located. The patent contemplated an exterior framework so as to hold the tube correctly, but this would add considerably to the expense. Second, in order for the tube to fold flat for shipping, the paper layers would have to be very thin, and this thinness led to bulging, and possible form failure, particularly at the bottom of the column where the pressures were highest. Again, this would require reinforcement on the outside, defeating the purpose of the collapsible tube form. Third, the patent contemplates an alternative for vertically supporting the tube by cutting a series of notches in the upper end, which are folded outwardly over a circular supporting framework. Again, this would require additional bracing and labor, obviating the benefits of the collapsible form.

OBJECT AND SUMMARY OF THE INVENTION

Accordingly, it is the object of this invention to provide an improved collapsible tube form that overcomes the problems set forth above.

The above and other objects and advantages of the present invention are achieved by the discovery that such forming tubes may be fabricated from fabric with one or more longitudinal tabs running the full length of the tube. Each tab is sandwiched between two vertical support members, which are used to properly locate the tube on the job site, before filling with concrete. This invention also contemplates the use of a woven fabric of sufficient strength that bulging will not occur, while at the same time being able to fold flat. The fabric is joined into a tube by welding (heat lamination), sewing or zippering the edges together.

In a preferred embodiment, the fabric based forming tube is collapsed and folded into a small package to facilitate its storage and transportation. On the jobsite, the contractor cuts off the exact length of tube required for the column. The fabric tab is nailed or screwed between two vertical support members probably made from 75 mm by 200 mm lumber, and the assembly is placed vertically into position and braced. Concrete is then poured into the fabric tube so that it takes a cylindrical configuration across from the two vertical support members. After the concrete is hardened, the fabric tube can be left in place, or removed at the weld (heat lamination), zipper, or cut with a sharp knife.

BRIEF DESCRIPTION OF THE DRAWINGS

While some of the advantages of the present invention have been set forth above, other advantages will become apparent from the description of the preferred embodiment of this invention when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of the concrete forming tube used to form a column with a single longitudinal tab;

FIG. 2 is a perspective view of the concrete forming tube used to form a pad with multiple longitudinal tabs;

FIG. 3 is a vertical cross section of the tube when expanded with concrete showing two longitudinal tabs, one zipper to enable the form to be reused, and three flexible sheet form elements welded (heat laminated), or sewn together;

FIG. 4 is a perspective view showing the length of tube being cut from a larger package, and the longitudinal tab being stapled to the first vertical support member;

FIG. 5 is a perspective view showing the second vertical support member being nailed or screwed to the first vertical support member, thereby sandwiching the vertical support tab;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a perspective view of a preferred embodiment of a concrete forming tube used in accordance with the present invention as a concrete column and which is indicated generally at 10. The flexible sheet form element, or fabric 14 is joined to form a tube with the outside longitudinal edge forming a longitudinal tab 16. The longitudinal tab 16 can be seen at the top, sandwiched between the two vertical support members 18, 20. The vertical support members are braced with suitable lumber 22, and stakes 30 are used to support the lower end of each brace 22. In this embodiment, there is only one longitudinal tab 16 on the fabric tube 12, with the vertical support members and bracing occurring on one side of the tube only. The tube, when filled with concrete 26 will form a cylinder, and center itself directly across from the two vertical support members. Steel reinforcing 24 can be installed in the fabric tube after the form assembly 10 has been set up; or the reinforcing 24 installed first, and the fabric tube 12 slid over the steel.

FIG. 2 is a perspective view of a preferred embodiment of a concrete forming tube 12 used in accordance with the present invention as a concrete footing pad and which is indicated generally at 28. Stakes 30 are driven into the ground just outside the circumference of the proposed circular pad 28. The desired length of fabric tube 42 is cut with a utility knife 52 from the longer length 40, and the longitudinal tabs 16 are stapled 34 to each stake 30 to support the tube in the correct position. Larger diameter pads could have a multiplicity of longitudinal tabs and supporting stakes. Pads could range in diameter from 450 mm up to 3000 mm, with the fabric tube welded (heat laminated), or sewn together to achieve these diameters. Concrete 26 is placed inside the tube, and trowelled flat to the top of the fabric tube 12.

FIG. 3 is a cross section of the fabric tube 12 expanded as if by the concrete to show manufacturing details. Three flexible sheet form elements 14 of indefinite length and a specific width are welded (heat laminated), or sewn together at points 36 to form the correct diameter for the column or pad. Welding (heat lamination), is the preferable method of joining as sewing can weaken the joint and create small holes for the concrete to leak out. The longitudinal tabs run the full length of the tube, with a width 38 running past the joining width 36. This longitudinal tab is sandwiched between the two vertical support members 18, 20 to support the tube in the vertical position for proper location during the concrete pour. The width of the longitudinal tab 38 is usually the same as the width of the vertical support members 18, 20 to ensure proper positioning of the tab.

The manufacturing process must accurately align and weld (heat laminate), the fabric so that the correct diameter of the inflated tube is achieved. As the diameter of the tube increases, the hoop tension of the fabric will increase because of the increased concrete pressure. Therefore the thickness of the fabric and the width of the welded (heat laminated), or sewn joint must be correspondingly increased.

A zipper 44 is shown in FIG. 3. The zipper would be used where it is desirable to recycle the tube form to lower forming costs. The zipper would also have applications where it is needed to place a concrete column around an existing steel column, for example to protect a steel column in a warehouse from damage. The fabric overlap 46 protects the zipper from concrete damage when filling with concrete. The zipper would be either welded (heat laminated), or sewn to the fabric. Velcro or sticky tape 48 may be required to ensure the overlap stays flat when filling to protect the zipper from concrete damage.

The flexible sheet form element 14 is typically made from a woven polyethylene or polypropylene material, with about 12 tapes per inch in the warp and weft direction. The tapes are high density to achieve strength, and a low-density coating on either or both sides of the scrim could be added to ensure the concrete does not leak through the fabric. It would also be possible to increase the fabric strength by adding warp and weft elements made of carbon fiber, for example, which, when left in place would provide external reinforcing to the concrete.

FIG. 4 is an isometric view showing the fabric tube 12 being cut to the length 42 of a desired column 10, and the longitudinal tab 16 being positioned and stapled 34 to the first vertical support member 18. The tube shape and fabric thickness would only allow the tube to be wound on very large diameter rolls as otherwise the fabric will wrinkle excessively. Therefore packaging of the tube would be on very large rolls and folded, or festooned 40.

FIG. 5 is an isometric view showing the second vertical support member 20 being attached to the first member 18 using nails or screws 50. The two vertical support members provide support to the longitudinal tab and therefore to the fabric tube during the pouring of concrete. In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not purposes of limitation. 

1. A tube form for making a concrete column comprising: a. a fabric sheet made of woven plastic cut to an indefinite length and a predetermined width; b. a first longitudinal edge area and a second longitudinal edge area defined on the fabric sheet, the first longitudinal edge area and the second longitudinal edge area overlapping at a longitudinal overlap area, wherein the first longitudinal edge area and the second longitudinal edge area are heat laminated to each other at the longitudinal overlap area, wherein an outside surface of the first longitudinal edge area is heat laminated to an inside surface of the second longitudinal edge area; and c. a protruding longitudinal tab protruding from the second longitudinal edge area, wherein the fabric sheet forms a tube having a predetermined diameter.
 2. The tube form of claim 1, further comprising two vertical support members sandwiching the protruding longitudinal tab to provide support.
 3. The tube form of claim 2, wherein the flexible sheet form element is made of a woven plastic fabric about 12 tapes per inch in the warp and weft direction.
 4. The tube form of claim 1, further comprising a zipper that joins at a fifth longitudinal edge area and a sixth longitudinal edge area, wherein a user can release the zipper to release the tube form from a cast concrete column, further comprising a fabric overlap that protects the zipper.
 5. The tube form of claim 4, wherein the flexible sheet form element is made of a woven plastic fabric about 12 tapes per inch in the warp and weft direction.
 6. The tube form of claim 1, wherein the flexible sheet form element is made of a woven polyethylene fabric.
 7. The tube form of claim 1, wherein the flexible sheet form element is made of a woven polypropylene fabric.
 8. The tube form of claim 1, wherein the flexible sheet form element is made of a woven plastic fabric about 12 tapes per inch in the warp and weft direction.
 9. A tube form for making a concrete column comprising: a. a first fabric sheet made of woven plastic cut to an indefinite length and a predetermined width; b. a second fabric sheet made of woven plastic cut to an indefinite length and a predetermined width; c. a first longitudinal edge area and a second longitudinal edge area defined on the first fabric sheet; d. a third longitudinal edge area and a fourth longitudinal edge area defined on the second fabric sheet, wherein the first longitudinal edge area and the third longitudinal edge area overlap at a first longitudinal overlap area, wherein the second longitudinal edge area and the fourth longitudinal edge area overlap at a second longitudinal overlap area, wherein the first longitudinal edge area and the third longitudinal edge area are heat laminated to each other at the first longitudinal overlap area, wherein the second longitudinal edge area and the fourth longitudinal edge area are heat laminated to each other at the second longitudinal overlap area, wherein an outside surface of the first longitudinal edge area is heat laminated to an inside surface of the third longitudinal edge area; and e. a protruding longitudinal tab protruding from the third longitudinal edge area, wherein the first fabric sheet joined to the second fabric sheet forms a tube having a predetermined diameter.
 10. The tube form of claim 9, further comprising two vertical support members sandwiching the protruding longitudinal tab to provide support.
 11. The tube form of claim 10, wherein the flexible sheet form element is made of a woven plastic fabric about 12 tapes per inch in the warp and weft direction.
 12. The tube form of claim 9, further comprising a zipper that joins at a fifth longitudinal edge area and a sixth longitudinal edge area, wherein a user can release the zipper to release the tube form from a cast concrete column, further comprising a fabric overlap that protects the zipper.
 13. The tube form of claim 12, wherein the flexible sheet form element is made of a woven plastic fabric about 12 tapes per inch in the warp and weft direction.
 14. The tube form of claim 9, wherein the flexible sheet form element is made of a woven polyethylene fabric.
 15. The tube form of claim 9, wherein the flexible sheet form element is made of a woven polypropylene fabric.
 16. A prefabricated flexible forming tube for a concrete column or pad comprising: at least one flexible sheet element of specified length and width characterized in that the flexible sheet element is formed from woven fabric, and one longitudinal edge of the flexible sheet element is arranged in overlapping relationship with either: i)an opposing longitudinal edge of the same flexible sheet element whereby an outside surface of the flexible sheet element adjacent one of the longitudinal edges is fixed to an inside surface of the flexible sheet element to form a joint and so create the flexible forming tube of the specified length and diameter and a longitudinal tab is formed from the flexible sheet element between another of the longitudinal edges and the joint; or ii) a longitudinal edge of another the flexible sheet element whereby an outside surface adjacent to the longitudinal edge of one of the flexible sheet elements is fixed to an inside surface of the other of the flexible sheet elements to form a joint and a longitudinal tab is formed from the another flexible sheet element between the joint and a longitudinal edge of the other flexible sheet element, such that the joined flexible sheet elements create at least a portion of the flexible forming tube.
 17. A prefabricated flexible forming tube according to claim 16 wherein the tube is formed from a multiplicity of the flexible sheet elements, adjacent flexible sheet elements of the multiplicity being fixed together as claimed in claim 1 to form two or more the joints, each joint having an associated longitudinal tab.
 18. A prefabricated flexible forming tube according to claim 16 wherein at least two of the flexible sheet elements are longitudinally joined by temporary joining means.
 19. A prefabricated flexible forming tube according to claim 18 wherein the temporary joining means is a zipper.
 20. A prefabricated flexible forming tube according to claim 16 wherein the woven fabric is of such a nature that it adheres to a concrete column or pad formed by supplying the forming tube with foundation material, and the woven fabric cannot be stripped from the concrete column or pad.
 21. A prefabricated flexible forming tube according to claim 20 wherein said woven fabric contains high strength warp and/or weft elements to add structural strength to said concrete column or pad.
 22. A prefabricated flexible forming tube according to claim 21 wherein said warp and/or weft elements are made of carbon fibre. 